1. Field of the Invention
The instant disclosure relates to an active capacitive touch pen, and more particularly to an active capacitive touch pen using at least one varistor for determining the degree of pressure when a user uses the active capacitive touch pen on the handwritten board.
2. Description of Related Art
Conventional touch control devices may be classified into three types: resistive, electromagnetic and capacitive. Operation with a resistive touch control device requires a rigid pen tip to apply a significant force on the resistive touch control device in a very small area to accomplish deformation of the resistive touch sensor, and an electromagnetic touch control device requires a special battery powered pen for input; while the working principle of a capacitive touch control device relies on capacitive coupling, which takes place as soon as the capacitive touch sensor is touched by a conductive object, and the touch position can then be identified according to the variation in capacitance at the touch point. Therefore, a capacitive touch control device does not require an input pen that consumes electricity. Nor is it necessary to subject a capacitive touch sensor to concentrated pressure application for deformation, and thus a capacitive touch control device has a longer service life. Furthermore, mass production of capacitive touch control devices requires lower costs due to its simple construction, less components and higher yield rate.
A capacitive touch control device can be operated in many ways. The most common of all is using a conductor, for example a finger or a pen, to touch or slide on the surface of the capacitive touch control device, for the capacitive touch sensor thereof to generate a response signal. However, as capacitive touch control devices find more and more applications, the lower precision on position detection tends to hinder smoothness of operation where more precise and more efficient detection is required, such as in handheld devices. In order to enable enhanced precision on position detection, many people choose to use pens for capacitive touch input.